chore: update @eslint/core, add legacy-peer-deps, and use ESLint v10

[lumirlumir]

Prerequisites checklist

• I have read the contributing guidelines.

What is the purpose of this pull request?

This PR was motivated by #187 (comment).

Currently, when updating @eslint/core to v1.0.0, CI fails because @eslint/core@1.0.0 does not match ESLint v9

@eslint/core@1.0.0 includes type information for ESLint v10, which causes the type mismatch.

So, I've updated ESLint to >=10.0.0-alpha.0 <10.0.0 || ^10.0.1. (Ref: https://github.com/eslint/eslint/blob/main/packages/eslint-config-eslint/package.json#L66)

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When I update ESLint to >=10.0.0-alpha.0 <10.0.0 || ^10.0.1, the following error occurs, so I added the legacy-peer-deps option to .npmrc.

This change follows the approach in eslint/eslint#20281

What changes did you make? (Give an overview)

In this PR, I've updated @eslint/core, add legacy-peer-deps, and use ESLint v10 pre-release.

Related Issues

Ref: #187, #187 (comment), eslint/eslint#20281

Is there anything you'd like reviewers to focus on?

N/A

[eslint-github-bot]

Hi @lumirlumir!, thanks for the Pull Request

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[eslint-github-bot]

Hi @lumirlumir!, thanks for the Pull Request

The pull request title isn't properly formatted. We ask that you update the pull request title to match this format, as we use it to generate changelogs and automate releases.

• The length of the commit message must be less than or equal to 72

To Fix: You can fix this problem by clicking 'Edit' next to the pull request title at the top of this page.

Read more about contributing to ESLint here

[lumirlumir]

From ESLint v10, errors property in valid test case throws error, so I've removed it.

Ref: https://eslint.org/docs/next/use/migrate-to-10.0.0#stricter-rule-tester

[lumirlumir]

Counterpart PR in eslint/css: eslint/css#337

[mdjermanovic]

Since this is a dependency, will this affect end users who are still using ESLint v9?